The present invention relates to electrodes, and methods of making and using such electrodes.
As electronic devices become increasingly more compact and portable, the size of electrodes used in such devices must also necessarily decrease. Useful electrodes in such devices are typically flexible and are closely spaced, but electrically isolated conductive pathways. Typically, it is desirable, or even necessary, to use electrical devices that have abrasion resistant electrodes (i.e., electrodes that are protected from abrasion so as to provide robust consistent conductivity).
For example, glucose monitoring devices typically contain an electrical device having electrodes made from metal-coated, non-conductive films. In converting these metal-coated films into such electrodes, it is desirable, or necessary, to not scratch or abrade the metal-coated portion of the electrode. Scratching or abrading of the metal-coated portion of such an electrode may cause a total loss or a decrease in conductivity and may lead to premature failure of the electrical device containing such an electrode. A decrease in conductivity may result in a device providing an incorrect reading while still appearing to be functional. Conventional methods such as those methods that use conductive inks or thin metal wires or photolithography are relatively complex and costly. Other methods provide metal-coated plastic devices in which the protrusions of the device are conductive. A known embossing method embosses a metal-coated dielectric and then removes the metal coating from the protrusions using a flycutting technique.
While conventional techniques for making such electrodes are useful, there is a need to consistently make abrasion resistant electrodes, more easily and less costly.
In one aspect, the invention provides an abrasion resistant electrode comprising a polymeric substrate having two parallel non-conductive protrusions provided thereon and separated by a conductive valley, wherein the non-conductive protrusions have a coating of fractured metal.
In another aspect, the invention provides an electrical device comprising a plurality of abrasion resistant electrodes. The electrical device comprises a polymeric substrate having a plurality of non-conductive protrusions separated by conductive valleys, wherein the non-conductive protrusions have a coating of fractured metal.
In another aspect, the invention provides a method of making an abrasion resistant electrode or device. The method comprises the steps of providing a metal-coated non-conductive substrate comprising a thermoplastic polymer, contacting the metal-coated substrate with an embossing tool using sufficient heat and pressure to form the electrode or device. The embossing tool comprises a material having an engineering strain of less than 10%.
The electrodes and electrical devices of the present invention have simple construction and are relatively easy and inexpensive to make.